Process for making tetrapolyphosphoric phosphonates



Patented May 13, 1952 PROCESS FOR MAKING TETRAPOLYPHO'S- PHORICPHOSPHONATES Hugh J. Hagemeyer, Jr., Kingsport', Tenn.,'as-

signor to Eastman Kodak Company, Rochester,

N. Y., a'corporation of NevrJersey No Drawing. Application August 24,1950,

Serial No. 181,319

This invention relates to a method for making pesticidal phosphoruscompounds in which alkyl phosphonates are reacted with P205 underanhydrous conditions. The invention also relates to pesticidalcompositions comprising these phosphorus compounds.

Phosphoric esters have previously been prepared as shown, for instancein U. S. Patents Nos. 2397;42'2 and 2,400,577, and in Beilstein, volumeIV, pages'595-596. narily prepared by reacting triethyl phosphite orsome similar ester with an organic halide such as ethyl iodide or propylbromide. The products resulting from such reactions are employed as thestarting material for making pesticidal compounds in accordance with myinvention as described herein.

One object of my invention is to provide phosphorus compounds havingpesticidal properties. Another object of my invention is to provide aprocess by which neutral alkyl esters of poly phosphoric phosphonatesare produced. A further object of my invention is to provide newphosphorus containing chemical compounds. Other objects of my inventionwill appear herein.

Alkyl phosphonates are prepared in substantially quantitative yield byreacting an alkyl halide with trialkyl phosphite, for instance, byreacting ethyl iodide and trialkyl phosphite whereby the product diethylethyl phosphonate is formed such as in accordance with the followingequations:

The resulting product diethyl ethyl phosphonate is a clear, colorless,pleasant smelling liquid having a boiling point at mm. of Bil-81 C.

I have found that when this product is reacted with phosphorus pentoxidein the ratio of 1-6 mols of the dialkyl alkyl phosphonate to 1 mol ofP205 that a product is obtained having maximum insecticidal strength.The products obtained as a result of this reaction vary as regardschemical structure with the proportion of phosphonate and P205 which isreacted together. For instance, if the molar ratio of dialkyl alkylphosphonate to P205 is 2 to 1, the reaction may be as follows:

However, usilngiany of the ratios within the range specified herein,products are obtained charac- Alkyl phosphonates are ordi- 3 Claims.(Cl. 260461) terized by a high degree of kill as regards insects androdents.

The reaction between the P205 and the alkyl phosphonate is suitablycarried out in a-cooled reaction vessel equipped with an'ag-i'tator. Thedialkyl alkyl phosphonate'ester is placed in the reactor with or withoutan inert solvent'for reaction mediumand P2O5is slowly added to thevessel in the desired amount. For instance, the P205 is added over :aperiod of ten. minutes or more or in the alternativethe materials arecooled to 0 C. whereupon the P205 can be added at a rapid rate. Afterthe required amount of P205 is added, the mass is agitated and heated at50-70 C. for one to two hours which is usually sufficient time to effectcomposition of the reaction. In the case of the lower alkyl compoundsordinarily one-hour treatment is suflicient,

whereas with the phosphonate having alkyls or more than two carbonatoms, a longer time is as a rule desirable. The resulting productordinarily requires no purification but can be employed directly in thepreparing of insecticidal compositions. For instance, if a dust isdesired the phosphorus compound prepared can be mixed with a carriersuch as pyrophyllite or finely divided sulfur in the proportion of05-10% of the phosphorus compound. If the phosphorus compound is to beemployed as a spray, it may be dissolved in any inert liquid which is asolvent therefor. For instance, the lower alkyl compounds and theformation of a water solution is readily accompanied for sprayingpurposes.

Some of the phosphonates which may be employed as a starting material inmethods in accordance with my invention are diethyl ethyl phosphonate,diethyl propyl phosphonate, dipropyl ethyl phosphonate, dimethyl ethylphosphonate, dibutyl methyl phosphonate, dimethyl phenyl phosphonate,etc.

1 The following examples illustrate the preparation of pesticidalcompounds in accordance with my invention and the use of these compoundsfor insecticidal purposes. In the following examples any of thephosphonates mentioned can be substituted for diethyl ethyl phosphonate.

Example I :the addition had been completed, a reaction tem- .perature offill- C. was maintained for two -;hours and the mass was agitatedcontinuously until all of the P205 was reacted. The resulting Example IIA dust was prepared with products of Example I with flour, and theeffectiveness thereof was tested employing roaches. lhe concentrationsof ester used and the per cent of roaches killed in the times indicatedwere as follows:

Percent Kill Percent Ester 20 Min. 1 Hr. 2 Hrs.

All of the phosphorus compounds which may be prepared in accordance withthe disclosure herein are characterized by insecticidal properties. Whenused in the form of dust, it is desirable that the product have aconcentration of 05-10% in the composition. When used in the form of aspray, concentrations of (ml-0.5% are usually the most desirable.

I claim:

1. A process of preparing a pesticidal phosphorus compound whichcomprises reacting under anhydrous conditions a compound having theformula in which R represents alkyl of 1-4 carbon atoms and K representslower alkyl and aryl with P205 in the molar ratio of 1-6 parts of thephosphonate to one part of P205.

2. A method of preparing a pesticidal phosphorus compound whichcomprises reacting a dialkyl alkyl phosphonate the alkyl groups beingwithin the range of 1-4 carbon atoms with P205 in a molar ratio of 1-6parts of the phosphonate to one part of the P205. Y

3. A method of preparing a pesticidal phosphorus compound whichcomprises reacting diethyl ethyl phosphonate with P205 in a molar ratioin 1-6 parts of the former to one part of the latter.

HUGH J. HAGEMEYER, JR.

REFERENCES CITED UNITED STATES PATENTS Name Date Kosolapofi Mar. 26,1946 Number

1. A PROCESS OF PREPARING A PESTICIDAL PHOSPHORUS COMPOUND WHICHCOMPRISES REACTING UNDER ANHYDROUS CONDITIONS A COMPOUND HAVING THEFORMULA